Apparatus for recovery of liquids from solids



March 24; 1942. H. L. ALEXANDER ETAL 2,277,053

APPARATUS FOR RECOVERY OF LIQUIDS FROM SOLIDS Original Filed Aug. 31, 1936 H .L ALEXANDER H.I DUPONT AND FOULKE Patented 24, 1942 trans s'r PATENT or ies APPARATUS FOR RECOVERY OF LIQUIDS FROM SOLES Henry L; Alexander, Wilmington, and Hubert 1, Du Pont, Rockland, Bet, and Willing B. Foulke, Media, Pa, assignors to Delaware Chemical Engineering and Development Company, Wilmington, list, a corporation of Delaware Original application August 31, 1936, Serial No. 58,819, new Patent No. 2,150,899,. dated March 21, 1939. Divided and this application March 20, 1939, Serial No. 283,083

3 Claims. (01-. 210-55) This invention relates to an improved settling tank and to the process of recovering liquids conjunction with such apparatus.

An object of this invention, accordingly. is the development of an improved settling tank construction which is especially valuable for utilization in a liquid recovery system for the recovery of heavy or parting liquid when employed in conjunction with mineral separation apparatus and methods employing flotation principles. Other objects of this invention will-be apparent from the resulting disclosure of our preferred embodiment thereof.

Referring now to the drawings. Fig. 1 represents a plan view, partly cut away and in section, of our improved settling tank or separator. Fig. 2 is a section taken on the line tic-6a of Fig. l and looking in the direction of the arrows. 3

Fig. 3 is a vertical section taken on the line BbTGD of Fig. 1 and looking in the direction of the arrows. Fig. 4 is an enlarged section taken on the line tic-6c of Fig. 1, also looking in the direction of the,arrows.

Referring specifically to the construction illustrated in the drawing, the separating apparatus as a whole is designated by the numeral 6.- Liquid containing light suspensoidal matter is carried from a primary settling tank (not shown) to the settling tank or separator herein disclosed through a pipe whose discharge end is designated of hermetical sealing.

Tubular member Gill extends to the bottom of the tank, this bottom being represented generally by the numeral 62. There are provided openings Si! in the side of the tubular member above the .water or liquid line when the device is in operation. A cover for the tubular member, 6 l 3, is provided, through which discharge pipe 458 leads into the tubular member. The bottom of the tank 62, ls'in the form of a truncated cone, of which 62l is a sump connected to the truncation of the cone. This sump may be formed by passing-a plane diagonall through a cylinder.

vided with valve 623. A pipe conveying water under pressure, 624, is provided so that the water may be used for dislodging sludge from the bottom of the sump SZI if and when said sludge be-' comes too solid to be moved by pumps.

A rod 625 journalled inbearing 626 in plate 622 extends upwardly through the tank in a vertical position and passes out through stufllng box 6 in cover H3; Handle H6 is attached-to the.

upper end-of the rod 625. At the lower portion of the rod there are arms 626 attached thereto in such a manner as to be rotatable by and with I the handle SIG and the rod .625. Diagonal scrapers 621 are placed on arm 626 so that-their movement will dislodge collected sludge from the conical bottom B22 and push it toward-the sump 62L Water seal, covers 6|! are providedfor affording access to the interior of the apparatus. These covers are provided with extending legs or flanges which are immersed in a channel filled with water so as to form an efifectlve seal to prevent the escape of vapors from within the settling tank to the outer atmosphere. Angle member 630. of a depth which increases from one side of the tank to the other, is welded or otherwise connected to the inside of the tank 6 toward the .top thereof. There is provided a wooden .weir strip B 3l of circular form attached to angle member, 630'. A discharge box 633 is located at the lowest :pointof the channel formed by tank 6 and angle member 630. Pipe H5 is connected to the box 633. A circular channel 649 is suspended from f the top SI of the tank] within the weir and is provided with a lip 64! which is slightly lower than the top of the weir 63L Pipes 642 project inwardly from channel 640 toward the bottom of the tank. The tank 6 is supported by metal legs 65 attachedto the tank and supported from any desired supporting structure or apparatus.

In operation our improved settling tank or sep-' arator iunctions as follows. The liquid contain H mg light suspensoidal matter in'larg'eror smaller Numeral 822 represents a diagonal plane dividing the cylinder" SH and forming a diagonal bottom on the sump which directs the solids whichcollect therein toward discharge pip 620, which is pro- V erated as vents to relieve interior pressure.

- August 31, 1936, now Patent No. 2,150,899).

vibrations caused by the plunge of the liquid or water from the pipe 458 into the body of liquid within the tank are largely spent within the tube, so that the liquid within the remainder of the tank is comparatively quiet. The channel which is formed between the weir and the shell of the tank is sloped and increased in size toward its outlet. .The liquid which flows over the weir follows the slope downwardly to the box 633 and is carried by' the pipe M5 out of the apparatus andto any suitable place. This may be the headers 442 (not shown) which are described in our copending application previously referred to. Light 'scum tends to float on the surface of the liquid within the tank, and the direction of the liquid currents would in the normal course wash this scum over the weir 63L Openings 612 are opterposed between the weir and the pipe 558 is scum gutter 848. As the scum, floating on the surface of the weir and being drawn by the current toward the weir, floats over the edge Mi of the scum gutter, which is slightl lower than the weir and contacts the side of the scum gutter, the scum tends to precipitate therein. As it is precipitated its apparent specific gravity increases to the point where it will follow the tube 642 downwardly into the'lower section of the tank. where it will settle on the bottom and be drawn off with the sludge. The sludge which concentrates in the bottom is from time to time scraped toward the sump and pumped through valves 623 and pipes 620 to the sludge trap and still (not shown, but described and claimed in our copending application Ser. No. 98,819, filed If the pipe becomes blocked, it may. becleared by an injection of water through pipe 626.

- Although our improved apparatus and process havebeen described in conjunction with the mineral separation equipment disclosed in our copending application Ser. No. 98,819, and in connection with the sludge trap and-steam still shown in our copending application Ser. No. 98,819. now Patent No. 2.150,.899, neither the apparatus nor the process is limited to use in connection with that apparatus, butis of broad general-utility wherever separation ofallquids and settling of solids therein is to be carried out.

Thus, the provision of a separator or settling 4 tank with a scum trap for the purpose of coagu lating and -retuming scum or liquid fractions which tend to precipitate therein to a lower portion of the apparatus where the sludge settles by gravity is of general utility, and ianotnecessarily restricted to use in conjunction with the separation of minerals by flotation methods. *Although the preceding description of a preferred embodiment of our inventionhas referred to water and to heavy or parting liquid, both our still come within the purview of our invention, .its scope is not to be restricted to details characteristicof our preferred embodiment, given merely as illustrative, except as necessitated by the appended claims and by the prior art. In the claims the word liquid or liquids" means the liquid or'mixture of liquids in which the solid matter is suspended. We claim: 1. A settling tank for separating solid matter suspended in a liquidfrom said liquid which comprises; a tank of generally circular cross-section provided with a generally conical bottom; an inlet pipe centrally disposed within said settling tank and having its outlet end positioned below the normal level of liquid in said settling tank whereby a suspension of solids in liquid may be introduced through said inlet pipe into said settling tank adjacent the bottom of said tank and in such manner that the settling of solids previously introduced into said tank is not appre-- ciably disturbed by the introduction of further amounts of said suspension, said centrally disposed inlet pipe being in communication with a conduit for supplying a suspension of solids in liquids from an outside source to said settling tank; a circumferentially extending channel positioned within said settling tank and at the upper portion thereof, said channel paralleling the circumferential external wall of said settling tank and being provided with a weir portion over which supernatant liquid may flow from said settling tank into said circumferentially extending channel; a scum gutter pesi tioned closely adjacent said channel and closely slightly lower level than the level of said weir, whereby floating scum may be withdrawn from said supernatant liquid into said scum gutter before said supernatant liquid can overflow said weir into said circumferentially extending channel; means for returning said removed scum to the lower portion of said settling tank; a conduit for transporting said supernatantliquid from said circumferentially extending channel outside of said settling tank; and means for removing precipitated solids from the bottom of said settling tank.

2. A settling tank for separating solid matter suspended in a liquid from said liquid which comprises; a tank of generally circular cross-section provided with a generally conical bottom; an inlet pipe centrally disposed within said settling tank and having its outlet end positioned below the normal level of liquid in said settling tank whereby a suspension of solids in liquid may be introduced through said inlet pipe into said settling tank adjacent the bottom of said tank and in such manner that the settling of solids previously introduced into said tank is not appreciably disturbed by the introduction of further amounts of said suspension, said centrally disposed inlet pipe being in communication with a conduit for supplying a suspension of solids in liquids from an outside source to said settling tank; a circumferentially extending channel pcsitioned within said settling tank and at the upper portionthereof, said channel paralleling'the circumferential external wall of saidsettling tank and being provided with a weir portion over which supernatant liquid mayv flow from said settling tank into said circurn'ferentially extending channel; a scum gutter positioned closely adjacent said channel and closely paralleling said channel, said scum gutter being formed with an edge portion positioned at a slightly, lower level than the level of said weir, whereby floating scum may be withdrawn from said supernatant liquid into said scum gutter before said supernatant liquid can overflow said weir into said circumferentially extending channel; means for returning said removed scum to the lower portion of said settling tank; a conduit for transporting said supernatant liquidfromsaid circumferentially extending channel outside of said settling tank; a discharge outlet positioned in the bottom of said tank for removing precipitated solids from the bottom of said settling tank; and a water jet positioned in said outlet and assisting in the re-- moval of said precipitated solid matter from said settling tank.

3. A settling tank for separating solid matter suspended in liquid from said liquid which comprises; a tank of generally circular cross-section provided with a generally conical bottom; an inlet pipe centrally disposed within said settling tank and having its outlet end positioned below the normal level of liquid in said settling tank whereby a suspension of solids in liquids may be introduced through said inlet pipe into said tank and in such manner that the settling of solids previously introduced into said tank is not appreciably disturbed by the introduction of further amounts of said suspension, said centrally disposed inlet pipe being in communication with a conduit for supplying a suspension of solids in liquids from an outside source to said settling tank; an anglemember with anupstanding leg positioned within said settling tank adjacent the upper portion thereof, said upstanding leg portion paralleling the circumferential external wall of said settling tank and said angle member forming therewith a circumferentially extending channel within said settling tank and at the upper portion thereof, said upstanding leg consti tuting a weir over which supernatant liquid may flow from said settling tank to said circumferentially extending channel; a scum gutter positioned closely adjacent said channel and closely paralleling said angle member, said scum gutter being formed with an edge portion positioned at a slightly lower level than the level of said weir, whereby floating scum may be withdrawn from said supernatant liquid into said scum gutter before said supernatant liquid can overflow said 'weir into said circumferentially extending channel; means for returning said removed scum to the lower portion of said settling tank; a conduit for transporting said supernatant liquid from said circumferentially extending channel outside of said settling tank; means for stirring said precipitated solids in the lower portion of said settling tank; and a conduitior removing said precipitated solids from the bottom portion of said settling tank.

HENRY L. ALEXANDER. HUBERT I. DU PONT. WIIJJNQBFQUIKE. 

